December 2025 seminar - Ilfa Gabitova and Thibault Lechien скачать в хорошем качестве

December 2025 seminar - Ilfa Gabitova and Thibault Lechien

Modeling efforts in studying recent post-mass transfer Be binaries: case of HD 698 - Ilfa Gabitova HD 698 is a newly characterized Be + bloated B binary, caught in the transitional phase following mass transfer when the stripped donor remains luminous. We combine orbital solution with SED radiative transfer modeling to constrain its parameters. Evidence for efficient mass transfer in interacting binary systems - Thibault Lechien Abstract: The lives and deaths of massive stars are strongly affected by binary interactions. A key uncertainty in our understanding of these interactions is the efficiency of mass transfer, which is the fraction of mass retained by the accretor during Roche-lobe overflow. Recently, new interferometric measurements with VLTI/GRAVITY and the CHARA Array led to constraints on the masses and orbits for a sample of rapidly rotating stars with stripped companions (Be+sdOB systems). We use these post-interaction binaries to show that mass transfer in intermediate mass stars is far more efficient than commonly assumed. Together with complementary studies at higher masses, this challenges widely adopted models that assume very non-conservative mass transfer, whether limited by spin-up or by the accretor's thermal timescale. Our results have broad consequences for the predicted masses, orbital properties, and compositions of binary stars, and for the formation pathways of compact objects.